Tech ARP posted an editorial on PhysX
>> NVIDIA Launches PhysX
You will need to install the latest 177.39 ForceWare driver in addition to the PhysX driver. At this moment, PhysX support has only been enabled for those four GPUs. NVIDIA will progressively enable PhysX support in the other GeForce 9 and GeForce 8 graphics over the next few weeks.
>> NVIDIA Launches PhysX
